Control channel detection for multiple implicit identifiers

ABSTRACT

A method for identifying matched mobile stations includes receiving by a first mobile station signals from a plurality of mobile stations located within a threshold distance of the first mobile station, identifying a first group of mobile stations of the plurality of mobile stations, and receiving uni-cast control information from a network entity. For each mobile station of a first group, the method includes identifying a matched mobile station based upon first data of a mobile station of the first group effectively matching second data of a mobile station of a second group. One operation includes generating a descrambled information element for each matched mobile station of the first group by using the first scrambling sequence that is associated with the matched mobile station to descramble the scrambled information element of the mobile terminal of the second group that is matched to the mobile terminal of the first group.

CROSS-REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. §119(e), this application claims the benefit ofearlier filing date and right of priority to Provisional Application No.61/141,194, filed on Dec. 29, 2008, the contents of which areincorporated by reference herein in their entirety.

FIELD OF THE INVENTION

The present invention relates to wireless communications, and inparticular, to wireless communication techniques.

DESCRIPTION OF THE RELATED ART

In a cellular system, a base station (BS) or a relay station (RS)transmits control information to one or more mobile stations (MSs) orsub-ordinate RSs. Generally, an MS may have to monitor multipleidentifiers (IDs), such as a broadcast ID, a unicast ID, and a multicastID.

For example, an MS may need to monitor the control information of otherMSs in certain situations, such as when performing network codingtechniques. As another example, an RS may need to monitor multiple IDs,such as the ID of each of the MSs in communication with the RS.

Access link network coding is one type of network coding technique wherea transmitter transmits a network coded packet to a parent station andto one or more MSs. Access link network coding usually requires an MS toreceive the uplink (UL) resource assignments of neighboring MSs whichmay be provided by an RS, for example. Moreover, access link networkcoding usually requires an MS to know the Mobile Station Group (MSG)report assignments of other MSs, where an MSG report is a report sentfrom an MS to its parent station describing MSs that are nearby the MS.As such, the MS may be required to monitor UL scheduling assignments toother MSs.

Typically, a BS does not explicitly transmit the ID of an MS(hereinafter referred to as an “MS ID”) with the control channel blockbecause the BS applies, for example, MS ID-specific scrambling ormasking to the control information or the cyclic redundancy code (CRC).Consequently, when an MS or RS is required to monitor multiple IDs, theMS or RS may be required to iteratively perform several descramblingoperations and CRC calculations in order to determine which MS IDs arescheduled.

SUMMARY

In various embodiments, a method for identifying matched mobile stationsincludes receiving by a first mobile station signals from a plurality ofmobile stations located within a threshold distance of the first mobilestation, identifying a first group of mobile stations of the pluralityof mobile stations, the first group being those mobile stations thatmeet a threshold requirement; and receiving uni-cast control informationfrom a network entity, wherein the uni-cast control informationcomprises scheduling information for a second group of mobile stations,and wherein the scheduling information for each mobile station of thesecond group comprises a scrambled information element and a scrambledcyclic redundancy check (CRC), wherein each mobile station of the secondgroup is a candidate for matching to a mobile station of the firstgroup. For each mobile station of the first group, the method furtherincludes identifying a first scrambling sequence to be applied to aninformation element of an associated mobile station and a secondscrambling sequence to be applied to a CRC of the associated mobilestation, and obtaining first data by performing a CRC on the firstscrambling sequence, which is then effectively logically XOR-ed to thesecond scrambling sequence. In addition, for each mobile station of thesecond group, the method includes obtaining second data by performing aCRC on the scrambled information element, which is then effectivelylogically XOR-ed to the scrambled CRC. Further, for each mobile stationof the first group, the method includes identifying a matched mobilestation based upon the first data of a mobile station of the first groupeffectively matching the second data of a mobile station of the secondgroup. One operation includes generating a descrambled informationelement for each matched mobile station of the first group by using thefirst scrambling sequence that is associated with the matched mobilestation to descramble the scrambled information element of the mobileterminal of the second group that is matched to the mobile terminal ofthe first group. Alternative embodiments include a mobile station beingconfigured to function using, for example, the foregoing operations.

These and other embodiments will also become readily apparent to thoseskilled in the art from the following detailed description of theembodiments having reference to the attached figures, the presentdisclosure not being limited to any particular embodiment disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and features of the present disclosure willbecome more apparent upon consideration of the following description ofembodiments, taken in conjunction with the accompanying drawing figures.

FIG. 1 illustrates an exemplary communication system in accordance withvarious embodiments of the invention.

FIG. 2 is a block diagram of an exemplary communication network inaccordance with various embodiments of the present invention.

FIG. 3 is a block diagram showing in more detail various componentswhich may be implemented in a mobile station according to variousembodiment of the present invention.

FIG. 4 illustrates an example of MSG report allocations in accordancewith various embodiments of the invention.

FIG. 5 illustrates an example of MSG report allocations in accordancewith various embodiments of the invention.

FIGS. 6A and 6B are flowcharts depicting methods for identifying matchedmobile stations according to various embodiments of the presentinvention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In the following detailed description, reference is made to theaccompanying drawing figures which form a part hereof, and which show byway of illustration specific embodiments of the invention. It is to beunderstood by those of ordinary skill in this technological field thatother embodiments may be utilized, and structural, electrical, as wellas procedural changes may be made without departing from the scope ofthe present invention. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or similarparts.

Various embodiments will be presented herein in the context of awireless communication network and associated entities configured inaccordance with the IEEE 802.16 standards family commonly referred to asWiMAX. However, alternatives to such implementations are envisioned andteachings with regard to the WiMAX standard are generally applicable toother standards and air interfaces as well. Moreover, the use of certainterms to describe various embodiments should not limit such embodimentsto a certain type of wireless communication system, such as WiMAX.Various embodiments are also applicable to other wireless communicationsystems using different air interfaces and/or physical layers including,for example, frequency division multiple access (FDMA), time divisionmultiple access (TDMA), code division multiple access (CDMA), widebandCDMA (W-CDMA), and universal mobile telecommunications system (UMTS),the long term evolution (LTE) of the UMTS, and the global system formobile communications (GSM). By way of non-limiting example only,further description will relate to a WiMAX communication system, butsuch teachings apply also to other system types.

FIG. 1 illustrates an exemplary communication system 100 in accordancewith various embodiments of the invention.

As shown in FIG. 1, the communication system 100 includes a base station(BS) 102, a relay station (RS) 104, and mobile stations (MSs) 106 a, 106b, and 106 c. The BS 102 can communicate with the RS 104 via signal 111.Each MS in the communication system 100 can communicate with the BS 102via the RS 104. The MS groups MSG1, MSG2, and MSG3 will be described inmore detail in conjunction with later figures.

FIG. 2 is a block diagram of an exemplary communication network inaccordance with various embodiments of the present invention. In thisfigure, communication network 200 includes a home network serviceprovider (“home NSP”) 260, a visited network service provider (“visitedNSP”) 262, an access service network (ASN) 264, access service networks266, access service provider networks 268 a and 268 b. MSs 106 areseparately shown in communication with respective serving BSs 270 a, 270b. In some embodiments, the BSs 270 a, 270 b, are implemented in amanner similar to that of the BSs of FIG. 1.

A network service provider, such as home NSP 260 or visited NSP 262, mayinclude a business entity that provides IP connectivity and WiMAXservices to WiMAX subscribers compliant with the service level agreementit establishes with WiMAX subscribers. A technique for providing theseservices includes the NSP establishing an agreement with one or morenetwork access providers, which are commonly implemented as businessentities providing WiMAX radio access infrastructure to one or moreWiMAX network service providers.

ASN 264 typically includes a logical boundary and represents anaggregation of functional entities and corresponding message flowsassociated with the access services. ASN 264 often includes a boundaryfor functional interoperability with WiMAX clients, WiMAX connectivityservice functions, and aggregation of functions embodied by differentvendors, for example.

In FIG. 2, ASN 264 is shown sharing R1 reference point (RP) with MSs106, R3 RP with a connectivity service network (CSN) of visited NSP 262,and a R4 RP with ASN 266. ASN 264 typically includes one or more basestations and one or more instances of an ASN gateway (ASN-GW). The R4reference point is typically implemented for control and bearer planesfor interoperability between similar or heterogeneous ASNs.Interoperability between various types of ASNs may be accomplished usingthe specified protocols and primitives exposed across R1, R3 and R4reference points.

In some embodiments, the depicted base stations are entities that embodya full instance of the WiMAX media access control (MAC) and physical(PHY) layers in compliance with the relevant transmission protocol. Inthe embodiment of FIG. 2, these base stations may be configured tofunction or otherwise implement the IEEE 802.16 suite of applicablestandards, and may host one or more access functions. In some scenarios,the base stations each represent one sector with one frequencyassignment and incorporates scheduler functions for both uplink anddownlink resources.

Connectivity (e.g., reachability) of BSs 270 a, 270 b to more than oneASN-GW may be required or desired to facilitate load balancing,redundancy, and the like. Note that each BS 270 a and/or 270 b is alogical entity, and a physical implementation of such logical entitiesmay implement one or more base stations.

Reference point R1 typically includes protocols and procedures tofacilitate communication between MS 106 and ASN 264. If desired,reference point R1 may also include additional protocols related to themanagement plane.

Reference point R2 generally includes protocols and procedures tofacilitate communication between MS 110 and one or more CSNs. Referencepoint R2 is shown as a logical interface such that it does not reflect adirect protocol interface between a MS and the CSN.

The authentication part of reference point R2 is shown between MSs 106and the CSN of home NSP 260. However the ASN and CSN of visited NSP 262may partially or completely process the aforementioned procedures andmechanisms. Reference point R2 may also support IP host configurationmanagement between the MSs 110 and the CSN (of either the home NSP 260or the visited NSP 262).

Reference point R3 often includes a set of control plane protocolsbetween ASN 264 and the CSN to support authentication, authorization,accounting (AAA), and the like, associated with a user (e.g., MS 106),and subscribed services across different access technologies. Forexample, AAA may include mechanisms for secure exchange and distributionof authentication credentials and session keys for data encryption.

Reference point R4 often includes a set of control and bearer planeprotocols originating/terminating in various functional entities of anASN that coordinate the mobility of MSs 106 between ASNs and ASN-GWs. Insome scenarios, R4 is the only interoperable RP between similar orheterogeneous ASNs.

Reference point R5 may include a set of control plane and bearer planeprotocols for internetworking between the CSN of the home NSP 260 andmay be operated by the visited NSP 262.

The ASN gateway (ASN-GW) in ASN 264 is shown as a logical entity thatrepresents an aggregation of control plane functional entities that areeither paired with a corresponding function in the ASN (e.g., a BSinstance), a resident function in the CSN, or a function in another ASN,such as ASN 266. The ASN-GW may also perform bearer plane routing orbridging function. ASN-GW implementation may include redundancy andload-balancing among several ASN-GWs.

In some embodiments, for each MS 106, a base station may be associatedwith only one default ASN GW. However, other embodiments permit ASN-GWfunctions for each MS to be distributed among multiple ASN-GWs locatedin one or more ASNs.

Reference point R6 generally includes a set of control and bearer planeprotocols for communication between the BSs 270 a and 270 b and theASN-GW. The bearer plane usually includes an intra-ASN data path betweeneach of the BSs 270 a and 270 b and the ASN gateway. The control planemay include protocols for data path establishment, modification, andrelease control in accordance with the MS mobility events.

Reference point R7 may include an optional set of control planeprotocols (e.g., for AAA and policy coordination in the ASN gateway), aswell as other protocols for coordination between the various groups offunctions identified in the reference point R6.

The decomposition of the ASN functions using the R7 protocols isoptional.

Reference point R8 may include a set of control plane message flows andoptionally bearer plane data flows between BSs 270 a and 270 b tofacilitate handover. The bearer plane often includes protocols thatallow the data transfer between BSs involved in handover of a certainMS, such as MSs 106. The control plane may include an inter-BScommunication protocol and additional set of protocols that allowcontrolling of the data transfer between the BSs involved in handover ofa certain MS.

In some embodiments, communication network 200 may include relaystations to provide improved coverage and/or capacity by establishingLayer-3 (L3) connectivity with an MS configured to communicate using adesired protocol (e.g., IEEE 802.16e, IEEE 802.16m, and the like).

FIG. 3 is a block diagram showing in more detail various componentswhich may be implemented in an MS 106 according to various embodiment ofthe present invention. The MS 106 corresponds to the MSs 106 a through106 c described herein. It is understood that greater or fewercomponents than those shown may be implemented.

Referring to FIG. 3, the MS 106 may include a wireless communicationunit 310, an audio/video (A/V) input unit 320, a user input unit 330, asensing unit 340, an output unit 350, a memory 360, an interface unit370, a controller 380, and a power supply unit 390. Two or more of thewireless communication unit 310, the A/V input unit 320, the user inputunit 330, the sensing unit 340, the output unit 350, the memory 360, theinterface unit 370, the controller 380, and the power supply unit 390may be incorporated into a single unit, or some of the wirelesscommunication unit 310, the A/V input unit 320, the user input unit 330,the sensing unit 340, the output unit 350, the memory 360, the interfaceunit 370, the controller 380, and the power supply unit 390 may bedivided into two or more smaller units.

The wireless communication unit 310 may include a broadcast receptionmodule 311, a mobile communication module 313, a wireless Internetmodule 315, a short-range communication module 317, and a GPS module319.

The broadcast reception module 311 receives a broadcast signal and/orbroadcast-related information from an external broadcast managementserver through a broadcast channel. Examples of a broadcast channelinclude a satellite channel and a terrestrial channel. The broadcastmanagement server may be a server which generates broadcast signalsand/or broadcast-related information and transmits the generatedbroadcast signals and/or the generated broadcast-related information ora server which receives and then transmits previously-generatedbroadcast signals and/or previously-generated broadcast-relatedinformation.

Examples of broadcast-related information include broadcast channelinformation, broadcast program information, and broadcast serviceprovider information. Examples of the broadcast signal include a TVbroadcast signal, a radio broadcast signal, a data broadcast signal, orthe combination of a data broadcast signal and either a TV broadcastsignal or a radio broadcast signal. The broadcast-related informationmay be provided to MS 106 through a mobile communication network. Inthis case, the broadcast-related information may be received by themobile communication module 313, rather than by the broadcast receptionmodule 311. The broadcast-related information may come in various forms,for example, electronic program guide (EPG) of digital multimediabroadcasting (DMB) or electronic service guide (ESG) of digital videobroadcast-handheld (DVB-H).

Broadcast reception module 311 may receive the broadcast signal usingvarious broadcasting systems such as digital multimediabroadcasting-terrestrial (DMB-T), digital multimediabroadcasting-satellite (DMB-S), media forward link only (MediaFLO),DVB-H, and integrated services digital broadcast-terrestrial (ISDB-T).In addition, the broadcast reception module 311 may be configured to besuitable for nearly all types of broadcasting systems other than thoseset forth herein.

The broadcast signal and/or the broadcast-related information receivedby the broadcast reception module 311 may be stored in memory 360.

The mobile communication module 313 transmits wireless signals to orreceives wireless signals from at least one or more of a base station,an external station, a relay station, and a server through a mobilecommunication network. The wireless signals may include various types ofdata according to whether the MS 106 transmits/receives voice callsignals, video call signals, or text/multimedia messages.

The wireless Internet module 315 may be a module for wirelesslyaccessing the Internet. The wireless Internet module 315 may be embeddedin the MS 106 or may be installed in an external device.

The short-range communication module 317 may be a module for short-rangecommunication. The short-range communication module 317 may use variousshort-range communication techniques such as Bluetooth®, radio frequencyidentification (RFID), infrared data association (IrDA), ultra wideband(UWB), and ZigBee®.

The GPS module 319 may receive position information from one or moresatellites (e.g., GPS satellites).

The A/V input unit 320 may be used to receive audio signals or videosignals. The A/V input unit 320 may include one or more cameras 321 anda microphone 323. The camera 321 processes various image frames such asstill images or moving images captured by an image sensor during a videocall mode or an image capturing mode. The image frames processed by thecamera 321 may be displayed by a display module 351.

The image frames processed by the camera 321 may be stored in the memory360 or may be transmitted outside the MS 106 through the wirelesscommunication unit 310. The MS 106 may include more than two cameras.

The microphone 323 receives external sound signals during a call mode, arecording mode, or a voice recognition mode with the use of a microphoneand converts the sound signals into electrical sound data. In the callmode, the mobile communication module 313 may convert the electricalsound data into data that can be readily transmitted to a mobilecommunication base station and then output the data obtained by theconversion. The microphone 323 may use various noise removal algorithmsto remove noise that may be generated during the reception of externalsound signals.

The user input unit 330 generates key input data based on user input forcontrolling the operation of the MS 106. The user input unit 330 may beimplemented as a keypad, a dome switch, a touch pad (either staticpressure or constant electricity), a jog wheel, or a jog switch. Inparticular, if the user input unit 330 is implemented as a touch pad andforms a mutual layer structure along with the display module 351, theuser input unit 330 and the display module 351 may be collectivelyreferred to as a touch screen.

The sensing unit 340 determines a current state of the MS 106 such aswhether the MS 106 is opened or closed, the position of the MS 106 andwhether the MS 106 is placed in contact with a user. In addition, thesensing unit 340 generates a sensing signal for controlling theoperation of the MS 106.

For example, when the MS 106 is a slider-type mobile phone, the sensingunit 340 may determine whether the MS 106 is opened or closed. Inaddition, the sensing unit 340 may determine whether the MS 106 ispowered by the power supply unit 390 and whether the interface unit 370is connected to an external device.

The sensing unit 340 may include an acceleration sensor 343.Acceleration sensors are a type of device for converting an accelerationvariation into an electric signal. With recent developments inmicro-electromechanical system (MEMS) technology, acceleration sensorshave been widely used in various products for various purposes. Forexample, an acceleration sensor may be used as an input device for acomputer game and may sense the motion of the human hand during acomputer game.

Two or three acceleration sensors 343 representing different axialdirections may be installed in the MS 106. Alternatively, only oneacceleration sensor 343 representing a Z axis may be installed in the MS106.

The output unit 350 may output audio signals, video signals, and alarmsignals. The output unit 350 may include the display module 351, anaudio output module 353, and an alarm module 355.

The display module 351 may display various information processed by theMS 106. For example, if the MS 106 is in a call mode, the display module351 may display a user interface (UI) or a graphical user interface(GUI) for making or receiving a call. If the MS 106 is in a video callmode or an image capturing mode, the display module 351 may display a UIor a GUI for capturing or receiving images.

If the display module 351 and the user input unit 330 form a mutuallayer structure and are thus implemented as a touch screen, the displaymodule 351 may be used not only as an output device but also as an inputdevice. If the display module 351 is implemented as a touch screen, thedisplay module 351 may also include a touch screen panel and a touchscreen panel controller.

The touch screen panel is a transparent panel attached onto the exteriorof the MS 106 and may be connected to an internal bus of the MS 106. Thetouch screen panel monitors whether the touch screen panel is touched bya user. Once a touch input to the touch screen panel is detected, thetouch screen panel transmits a number of signals corresponding to thetouch input to the touch screen panel controller.

The touch screen panel controller processes the signals transmitted bythe touch screen panel and transmits the processed signals to thecontrol unit 380. The control unit 380 then determines whether a touchinput has been generated and which part of the touch screen panel hasbeen touched based on the processed signals transmitted by the touchscreen panel controller.

As described above, if the display module 351 and the user input unit330 form a mutual layer structure and are thus implemented as a touchscreen, the display module 351 may be used not only as an output devicebut also as an input device. The display module 351 may include at leastone of a liquid crystal display (LCD), a thin film transistor (TFT)-LCD,an organic light-emitting diode (OLED), a flexible display, and athree-dimensional (3D) display.

The MS 106 may include two or more display modules 351. For example, theMS 106 may include an external display module and an internal displaymodule.

The audio output module 353 may output audio data received by thewireless communication unit 310 during a call reception mode, a callmode, a recording mode, a voice recognition mode, or a broadcastreception mode or may output audio data present in the memory 360. Inaddition, the audio output module 353 may output various sound signalsassociated with the functions of the MS 106 such as receiving a call ora message. The audio output module 353 may include a speaker and abuzzer.

The alarm module 355 may output an alarm signal indicating theoccurrence of an event in the MS 106. Examples of the event includereceiving a call signal, receiving a message, and receiving a keysignal. Examples of the alarm signal output by the alarm module 355include an audio signal, a video signal, and a vibration signal.

The alarm module 355 may output a vibration signal upon receiving a callsignal or a message. In addition, the alarm module 355 may receive a keysignal and may output a vibration signal as feedback to the key signal.

Once a vibration signal is output by the alarm module 355, the user mayrecognize that an event has occurred. A signal for notifying the user ofthe occurrence of an event may be output by the display module 351 orthe audio output module 353.

The memory 360 may store various programs necessary for the operation ofthe controller 380. In addition, the memory 360 may temporarily storevarious data such as a phonebook, messages, still images, or movingimages.

The memory 360 may include at least one of a flash memory type storagemedium, a hard disk type storage medium, a multimedia card micro typestorage medium, a card type memory (e.g., a secure digital (SD) orextreme digital (XD) memory), a random access memory (RAM), and aread-only memory (ROM). The MS 106 may operate a web storage, whichperforms the functions of the memory 360 on the Internet.

The interface unit 370 may interface with an external device that can beconnected to the MS 106. The interface unit 370 may be a wired/wirelessheadset, an external battery charger, a wired/wireless data port, a cardsocket such as for a memory card or a subscriber identification module(SIM)/user identity module (UIM) card, an audio input/output (I/O)terminal, a video I/O terminal, or an earphone.

The interface unit 370 may receive data from an external device or maybe powered by an external device. The interface unit 370 may transmitdata provided by an external device to other components in the MS 106 ormay transmit data provided by other components in the MS 106 to anexternal device.

The controller 380 may control the general operation of the MS 106. Forexample, the controller 380 may perform various control operationsregarding making/receiving a voice call, transmitting/receiving data, ormaking/receiving a video call.

The controller 380 may include a multimedia play module 381, which playsmultimedia data. The multimedia play module 381 may be implemented as ahardware device and may be installed in the controller 380.Alternatively, the multimedia play module 381 may be implemented as asoftware program.

The power supply unit 390 is supplied with power by an external powersource or an internal power source and supplies power to othercomponents in the MS 106.

Referring back to FIG. 1, each MS can be a member of one or more MSgroups (MSGs). For example, MS 106 a, MS 106 b, and MS 106 c maintainthree separate MS groups, such as MSG1, MSG2, and MSG3, respectively. Asillustrated, however, depending on the geographic location and proximityof the MSs 106 a, 106 b, and 106 c with respect to one another, the MSsmay be located within the perimeter of a single MSG such as MSG2.

For example, the BS 102 and the RS 104 may receive MSG information ofeach MS via an MSG report. Typically, the MSG information provided by anMS in the MSG report includes a group of neighboring MSs from which theMS is capable of successfully receiving uplink transmissions. The MSGinformation of the MS may be received periodically or repeatedly, asdescribed below.

In one embodiment, the MSG information of one MS may be receivedasynchronously with respect to the MSG information received from otherMSs. For example, if the MS 106 b is able to receive an MSG report fromthe MS 106 a, the MS 106 b can include the MS 106 a in the next MSGreport provided by the MS 106 b.

In accordance with one embodiment, the MSG information of an MS mayaffect the transmission scheduling of the BS 102 or RS 104 because thescheduler of the BS 102 or RS 104 may prefer to pair an uplink (UL)transmission from an MS in an MSG where the BS 102 has a scheduleddownlink transmission to take advantage of the benefits of networkcoding.

It is noted, however, that access link network coding often requireseach MS in the communication system 100 to receive the UL resourceassignments of neighboring MSs as determined, for example, by the RS104. Moreover, access link network coding may also require each MS to benotified of the MSG reporting assignments of other MSs. As such, each MSmay monitor additional identifiers (IDs) of other MSs.

In one embodiment, the UL resource assignment of a neighboring MS, whichis also referred to as a uni-cast control information message, can beincluded in an encoded message which is transmitted by the RS 104 to anintended MS.

For example, the UL resource assignment can be included in aninformation element (IE) and the RS 104 can generate a cyclic redundancycheck (CRC) based on the IE. Thereafter, the IE and CRC can each bescrambled using one or more scrambling sequences specific to the ID ofthe intended receiver. For example, the IE can be scrambled using afirst scrambling sequence (S₁) based on the ID of the intended MS togenerate a scrambled IE (IE_(S)) and the CRC can be scrambled using asecond scrambling sequence (S₂) based on the ID of the intended MS togenerate a scrambled CRC (CRC_(S)).

The RS 104 can then encode the IE_(S) and the CRC_(S) into a singlemessage. For example, the RS 104 can concatenate the IE_(S) and theCRC_(S) to generate the concatenated message IE_(S)|CRC_(S), where thesymbol “|” indicates concatenation. The RS 104 can then transmit theconcatenated message IE_(S)|CRC_(S) to the intended MS.

Typically, for an MS to decode an encoded message that includes a ULresource assignment of other MSs, that is, the message IE_(S)|CRC_(S),the MS generates S₁ and S₂ based on an MS ID, for each MS ID in an arrayof MS IDs. The MS then descrambles the message IE_(S)|CRC_(S) using S₁and S₂ to generate the message IE|CRC. The MS then generates a CRC basedon the IE, that is, CRC(IE) and compares the CRC to the CRC(IE).Therefore, the MS detects the MS ID if the CRC(IE) matches the CRC. Thisprocedure is repeated for each MS ID.

In one embodiment, an MS, such as MS 106 a in MSG1, can be configured toreceive and decode an encoded message that includes a UL resourceassignment of other MSs located in the MSG of the MS, such as MS 106 bin MSG1.

For example, for each MS; in the MSG of the MS 106 a, the MS 106 a cangenerate a first MS; scrambling sequence (S_(1i)) and a second MS;scrambling sequence (S_(2i)) based on the ID of the MS_(i) in the MSG.For example, the MS 106 a can generate S_(1i) and S_(2i) based on the IDof MS 106 b, since MS 106 b is in the MSG of the MS 106 a, that is,MSG1. In one embodiment, S_(1i) and S_(2i) can be generated by the MS106 a during a period when the MS 106 a is offline.

The MS 106 a can then perform a CRC operation on S_(1i) and can performan exclusive or (xor) operation on the result of the CRC operation andS_(2i) to generate a first code (C_(i)) for each MS_(i), as shown inequation 1. In one embodiment, each determined C_(i) may be stored in alist in the MS 106 a. The MS 106 a can then associate the scramblingsequence S_(1i) with the corresponding C_(i).

C _(i)=CRC(S _(1i))

S _(2i)  (equation 1)

After receiving the message IE_(S)|CRC_(S) intended for another MS, theMS 106 a can decode the user specific control channel (USCCH) IE ofanother MS. For example, the MS 106 a can perform a CRC operation on theIE_(S) and can perform an exclusive or operation on the result of theCRC operation and the CRC_(S) to generate a second code (C_(X)) as shownin equation 2.

C _(X)=CRC(IE _(S))

CRC_(S)  (equation 2)

The MS 106 a then proceed to determine whether C_(X) matches C_(i). IfC_(X) matches C_(i), then MS 106 a uses the S_(1i) corresponding to thecode C_(i) to descramble the IE_(S). It should be noted that thetechniques described herein involve a comparable amount of processing toconventional techniques where the MS ID is explicitly provided in theIE.

As explained below, CRC operations can be represented using polynomials.When polynomials are used, the coefficient of each order can correspondto the bit value of the order. Accordingly, a series of bits in a bitstream can be mapped to the coefficients in a polynomial to generate apolynomial representation of the bit stream. Therefore, for convenienceof explanation and unless specified otherwise, it should be understoodthat the polynomials herein described using functional notation, such asƒ(x), are generated based on polynomial representations of bit streams.

For example, the CRC described above can be generated according toequation 3:

$\begin{matrix}{{{m(x)}x^{L}} = {{{{{q(x)}{g(x)}} + {p(x)}}->{b(x)}} = {{{{m(x)}x^{L}} - {p(x)}}\mspace{70mu} = {{{{m(x)}x^{L}} + {p(x)}}\mspace{70mu} = {{q(x)}{g(x)}}}}}} & \left( {{equation}\mspace{14mu} 3} \right)\end{matrix}$

where the function g(x) is a polynomial representation of a CRCgenerator, the function m(x) is a polynomial representation of themessage, the function p(x) is a polynomial representation of theattached CRC, and the function b(x) is a polynomial representation ofthe transmitted signal. For example, the function m(x) can be a k^(th)order function, the function p(x) can be an L^(th) order function, andthe function b(x) can be an n^(th) order function, where n=k+L.

For example, a scrambling sequence based on an ID of an MS_(i) can begenerated according to equation 4:

S ^(i)(x)=S _(m) ^(i)(x)x ^(L) +S _(p) ^(i)(x)  (equation 4)

where the function S^(i)(x) is the total scrambling sequence, thefunction S_(m) ^(i)(x) is the scrambling sequence for the message, andthe function S_(p) ^(i)(x) is the scrambling sequence for the CRC. Forexample, the function S_(m) ^(i)(x) can be a k^(th) order function, thefunction S_(p) ^(i)(x) can be an L^(th) order function, and the functionS^(i)(x) can be an n^(th) order function, where n=k+L.

For example, after appending the CRC to the message, the signal to betransmitted can be represented by equation 5:

b(x)=m(x)x ^(L) +p(x)=q(x)g(x)  (equation 5)

The signal to be transmitted can then be scrambled using the functionS^(i)(x) described above according to equation 6:

$\begin{matrix}{{{b^{i}(x)} = {{{s^{i}(x)} \otimes {b(x)}}\mspace{50mu} = {{{{s_{m}^{i}(x)}{x^{L} \otimes {m(x)}}x^{L}} + {{s_{p}^{i}(x)} \otimes {p(x)}}}\mspace{50mu} = {{{s^{i}(x)} \otimes {q(x)}}{g(x)}}}}}\;} & \left( {{equation}\mspace{14mu} 6} \right)\end{matrix}$

The signal received by an MS can be represented by the function r(x),assuming that the signal is received without any errors, as shown inequation 7:

$\begin{matrix}{{r(x)} = {{b^{i}(x)}\mspace{40mu} = {{{s^{i}(x)} \otimes {b(x)}}\mspace{40mu} = {{{{s_{m}^{i}(x)}{x^{L} \otimes {m(x)}}x^{L}} + {{s_{p}^{i}(x)} \otimes {p(x)}}}\mspace{40mu} = {{{s^{i}(x)} \otimes {q(x)}}{g(x)}}}}}} & \left( {{equation}\mspace{14mu} 7} \right)\end{matrix}$

The determination of the CRC based on the message portion of the signalreceived by the MS can be performed with the function g(x) describedabove according to equation 8:

$\begin{matrix}{{CRC}_{m}^{i} = {{\left\{ {{s_{m}^{i}(x)}{x^{L} \otimes {m(x)}}x^{L}} \right\} {mod}\mspace{11mu} {g(x)}}\mspace{65mu} = {{\left\{ {{s_{m}^{i}(x)}x^{L}} \right\} {mod}\mspace{11mu} {{g(x)} \otimes \left\{ {{m(x)}x^{L\;}} \right\}}{mod}\mspace{11mu} {g(x)}}\mspace{65mu} = {\left\{ {{s_{m}^{i}(x)}x^{L}} \right\} {mod}\mspace{11mu} {{g(x)} \otimes {p(x)}}}}}} & \left( {{equation}\mspace{14mu} 8} \right)\end{matrix}$

An exclusive or operation can then performed on the determined CRC, thatis, CRC_(m) ^(i), the received CRC, that is, CRC_(S) ^(i), according toequation 9.

$\begin{matrix}{{{CRC}_{s}^{i} = {{s_{p}^{i}(x)} \otimes {p(x)}}}\begin{matrix}{{{CRC}_{m}^{i} \otimes {CRC}_{s}^{i}} = {\left\{ {{s_{m}^{i}( x)} x^{L}} \right\}  {mod}{ \;}{{{g( x)} \otimes {p( x)} \otimes {s_{p}^{i}( x)}} \otimes {p( x)}}}} \\{= {\left\{ {{s_{m}^{i}(x)}x^{L}} \right\} {mod}\mspace{11mu} {{g(x)} \otimes {s_{p}^{i}(x)}}}}\end{matrix}} & \left( {{equation}\mspace{14mu} 9} \right)\end{matrix}$

It should be noted that since the expression:

{s_(m) ^(i)(x)x^(L)} mod g(x)

s_(p) ^(i)(x)

of equation 9 depends solely on the MS ID and not data, the expressionindicates the MS ID. It is understood that the symbol “

” is used to symbolize a logical exclusive OR operation. In oneembodiment, the BS 102 can broadcast a bitmap in a USCCH IE at a fixedposition. For example, the bitmap can identify the IE_(S) in the USCCHthat a network-coding enabled MS needs to decode. With the assistance ofthe bitmap, a network coding-enabled MS does not need to decode the ULassignments and packet data associated with a UL packet which is notsuitable for network coding, such as a UL packet from an MS that is notin any other MSG of other MSs.

The assignment of MSG reports in accordance with various embodiments ofthe invention will now be discussed.

MSG reporting assignments can be similar to the VoIP resource assignmentbut on a slower time scale. The RS 104 assigns an MS configured toperform network coding to a bit position in the bitmap. In oneembodiment, the RS 104 assigns an MS to a bit position based on thefiltered channel quality indicator (CQI) of the MS and pilot reports ofneighboring pilots. For example, MSs having similar CQI and pilotreports are assigned to positions which are close to one another. The RS104 broadcasts the bitmap periodically. For example, the bitmap can bebroadcasted once every second in overhead messages.

For example, the BS 102 can generate a bitmap of “M” bits every second,where “M” is an integer representing the maximum number of MSs that mayperform network coding per each RS. For example, if there is an “N”number of active MSs configured to perform network coding, the BS 102can set “N” bits of the bitmap to “1.” If the bit position for an MS isset to ‘1,’ the MS determines its MSG reporting resource and timingbased on the number of other preceding bit positions that are set to‘1,’ as shown in the next paragraph.

In one embodiment, the communication system 100 enables a transmissionrate of 200 radio frames per second. The RS 104 schedules 2 n MSs tosend MSG reports for every radio frame, where n=N/200. In another words,MSGs are reported twice in one second from a network-coding enabled MS.For example, the i^(th) MS on the bitmap with a corresponding bit set to‘1’ can be denoted as MS_(j,k), where j=floor(i/2) and k=i %2. Anexample of MSG report allocations for MS_(j,k) where k=0 and k=1 areshown in FIGS. 4 and 5, respectively. In one embodiment, a fixedmodulation and coding scheme (MCS) can be used for transmitting the MSGreports.

It should be noted that the sets of MSs reporting at same time asMS_(j,k) are different in the two reporting opportunities for eachsecond. This minimizes the opportunities which can prevent someneighboring MSs from being discovered by MS_(j,k) due to concurrenttransmissions during periods when MS_(j,k) cannot hear. For example, theMS_(j,0) can be scheduled for UL transmissions, such as UL packet or DLfeedback, on radio frames f with f %2=0, such that the MS_(j,0) canalways hear from MSs with a k index value of 1. The formation of an MSGwill now be discussed with reference to FIG. 1.

In one embodiment, each MS in the communication system 100, such as MS106 a, 106 b, and 106 c, initially transmits an MSG report indicatingzero group members. Each of the MSs then proceeds to decode the MSGreport transmitted by another MS. For example, if an MS is able tosuccessfully decode the MSG report from a neighboring MS, the MSincludes in its MSG the MS ID of the neighboring MS. In one embodiment,the MS ID of the neighboring MS can be included in the MSG by anindication at the appropriate bit position in the bitmap.

In one embodiment, the i^(th) MS in the bitmap where k=0, that is,MS_(j,0), having high UL activities may be scheduled to transmit at evenframes and still be able to monitor or otherwise receive the MSG reportsof N-n+1 other MSs. The MS can also monitor or receive the soundingchannel of other MSs if the sounding channel assignment is based on thebitmap position. The MS transmits an updated MSG report at the scheduledopportunities.

The contents of an exemplary MSG report will now be discussed.

In one embodiment, an MSG report can include at least a bitmap index, aquality indicator, DL/UL activity indicators, a continuation indicator,or a format indicator. For example, the bit map index can identify theMSs that are in an MSG of an MS. The quality indicator can indicate thereceived signal strength or quality of the MSs in an MSG. The DL/ULactivity indicators can indicate the DL/UL activities of the MS. Thecontinuation indicator can be used to communicate to a BS that the MSGreport is a continuation of a previous MSG report. The format indicatorcan indicate whether the bitmap index is based on all bits of the bitmapor only on the positions set to “1.”

The size of an exemplary MSG report will now be discussed.

As discussed above, an MSG report can include at least a bitmap index, aCQI, DL/UL activity indicators, a continuation indicator, or a formatindicator. For example, the size of the bit map index can be determinedaccording to equation 10:

Bits_(Bitmapindex)=log₂(C _(x) ^(m))  (equation 10)

where “m” represents the number of MS IDs out of “M” or “N” IDs whichare reportable by the MS, such as MS IDs having a comparable CQI, andwhere “x” represents the maximum number of group members per MSG report.In one embodiment, the value of “M” or “N” depends on the formatindicator.

The CQI can include 2× bits to indicate one of four levels of signalstrengths corresponding to an MSG member of the MS. The DL/UL activityindicators can include 4 bits to indicate one of four levels ofactivities with respect to each of the DL and the UL. The continuationindicator and the format indicator can each include one bit.

Table 1 shows an exemplary MSG reporting overhead per MS.

TABLE 1 M m X frequency (Hz) bps 200 200 10 4 324 200 200 10 2 162 200200 5 4 192 200 200 5 2 96 200 100 10 4 280 200 100 10 2 140 200 100 5 4172 200 100 5 2 86 200 50 10 8 480 200 50 10 4 240 200 50 10 2 120 20050 5 8 304 200 50 5 4 152 200 50 5 2 76

The MSs indicated in a MSG report are the MSs whose MSG can be decodedby the reporting MS since the last report from the reporting MS. If thenumber of decodable MSs in this reporting period is greater than amaximum x, then MS picks the ones which are favorable to itself, e.g.,with greater signal strength, or DL/UL activities different from itself.

The MS maintains a set of MS IDs each of which has at least onedecodable MSG report in the last t duration. These are the MS IDs tomonitor for UL assignment.

FIGS. 6A and 6B are flowcharts depicting methods for identifying matchedmobile stations according to various embodiments of the presentinvention. As shown in FIG. 6A, the first mobile station, such as MS 106a, receives signals from a plurality of MSs, such as MS 106 b, locatedwithin a threshold distance of the first MS (S602).

A first group of MSs of the plurality of MSs are identified, the firstgroup being those MSs that meet a threshold requirement (S604). Uni-castcontrol information is then received from a network entity, where theuni-cast control information includes scheduling information for asecond group of MSs, where the scheduling information for each MS of thesecond group includes a scrambled information element (IE) and ascrambled CRC, where each MS of the second group is a candidate formatching to an MS of the first group (S606).

A first scrambling sequence to be applied to an IE of an associated MSand a second scrambling sequence to be applied to a CRC of theassociated MS is identified for each MS of the first group (S608). Firstdata is obtained for each MS of the first group by performing a CRC onthe first scrambling sequence, which is then effectively logicallyXOR-ed to the second scrambling sequence (S610). A second data isobtained for each MS of the second group by performing a CRC on thescrambled IE, which is then effectively logically XOR-ed to thescrambled CRC (S612).

A matched MS is identified for each MS of the first group based upon thefirst data of an MS of the first group effectively matching the seconddata of an MS of the second group (S614).

A descrambled IE is generated for each matched MS of the first group byusing the first scrambling sequence that is associated with the matchedMS to descramble the scrambled IE of the MS of the second group that ismatched to the MS of the first group (S616).

In alternative implementations, certain logic operations may beperformed in a different order, modified or removed and still implementpreferred embodiments of the present invention. Moreover, operations maybe added to the above described logic and still conform to assortedimplementations of the invention.

Furthermore, the described embodiments may be implemented as a method,apparatus or article of manufacture using standard programming and/orengineering techniques to produce software, firmware, hardware, or anycombination thereof. The term “article of manufacture” as used hereinrefers to code or logic implemented in hardware logic (e.g., anintegrated circuit chip, Field Programmable Gate Array (FPGA),Application Specific Integrated Circuit (ASIC), etc.) or a computerreadable medium (e.g., magnetic storage medium (e.g., hard disk drives,floppy disks, tape, etc.), optical storage (CD-ROMs, optical disks,etc.), volatile and non-volatile memory devices (e.g., EEPROMs, ROMs,PROMs, RAMs, DRAMs, SRAMs, firmware, programmable logic, etc.). Code inthe computer readable medium is accessed and executed by a processor.

The code in which preferred embodiments are implemented may further beaccessible through a transmission media or from a file server over anetwork. In such cases, the article of manufacture in which the code isimplemented may include a transmission media, such as a networktransmission line, wireless transmission media, signals propagatingthrough space, radio waves, infrared signals, etc. Of course, thoseskilled in the art will recognize that many modifications may be made tothis configuration, and that the article of manufacture may comprise anyinformation bearing medium known in the art.

The logic implementation shown in the figures describe specificoperations as occurring in a particular order. In alternativeimplementations, certain logic operations may be performed in adifferent order, modified or removed and still implement certainembodiments of the present invention. Moreover, operations may be addedto the above described logic and still conform to the describedimplementations.

The foregoing embodiments and advantages are merely exemplary and arenot to be construed as limiting the present invention. The presentteachings can be readily applied to other types of apparatuses andprocesses. The description of such embodiments is intended to beillustrative, and not to limit the scope of the claims. Manyalternatives, modifications, and variations will be apparent to thoseskilled in the art.

1. A method for identifying matched mobile stations, the methodcomprising: receiving by a first mobile station signals from a pluralityof mobile stations located within a threshold distance of the firstmobile station; identifying a first group of mobile stations of theplurality of mobile stations, the first group being those mobilestations that meet a threshold requirement; receiving uni-cast controlinformation from a network entity, wherein the uni-cast controlinformation comprises scheduling information for a second group ofmobile stations, wherein the scheduling information for each mobilestation of the second group comprises a scrambled information elementand a scrambled cyclic redundancy check (CRC), wherein each mobilestation of the second group is a candidate for matching to a mobilestation of the first group; for each mobile station of the first group,identifying a first scrambling sequence to be applied to an informationelement of an associated mobile station and a second scrambling sequenceto be applied to a CRC of the associated mobile station; for each mobilestation of the first group, obtaining first data by performing a CRC onthe first scrambling sequence, which is then effectively logicallyXOR-ed to the second scrambling sequence; for each mobile station of thesecond group, obtaining second data by performing a CRC on the scrambledinformation element, which is then effectively logically XOR-ed to thescrambled CRC; for each mobile station of the first group, identifying amatched mobile station based upon the first data of a mobile station ofthe first group effectively matching the second data of a mobile stationof the second group; and generating a descrambled information element,for each matched mobile station of the first group by using the firstscrambling sequence that is associated with the matched mobile station,to descramble the scrambled information element of the mobile terminalof the second group that is matched to the mobile terminal of the firstgroup.
 2. The method according to claim 1, wherein the thresholddistance of the first mobile station relates to a distance at which thefirst mobile station is able to receive the signals from the pluralityof mobile stations.
 3. The method according to claim 1, wherein thethreshold requirement is at least a defined signal strength, a definedsignal quality or a successful decoding of an uplink packet.
 4. Themethod according to claim 1, wherein the network entity comprises arelay station or a base station.
 5. The method according to claim 1,wherein the second group of mobile stations comprises a single mobilestation.
 6. The method according to claim 1, wherein the second group ofmobile stations comprises a plurality of mobile stations.
 7. A mobilestation, comprising: a receiver configured to receive signals from aplurality of mobile stations located within a threshold distance of themobile station and to receive uni-cast control information from anetwork entity; and a controller configured to: identify a first groupof mobile stations of the plurality of mobile stations, the first groupbeing those mobile stations that meet a threshold requirement, whereinthe uni-cast control information comprises scheduling information for asecond group of mobile stations, wherein the scheduling information foreach mobile station of the second group comprises a scrambledinformation element and a scrambled cyclic redundancy check (CRC),wherein each mobile station of the second group is a candidate formatching to a mobile station of the first group; identify for eachmobile station of the first group a first scrambling sequence to beapplied to an information element of an associated mobile station and asecond scrambling sequence to be applied to a CRC of the associatedmobile station; obtain for each mobile station of the first group firstdata by performing a CRC on the first scrambling sequence, which is theneffectively logically XOR-ed to the second scrambling sequence; obtainfor each mobile station of the second group second data by performing aCRC on the scrambled information element, which is then effectivelylogically XOR-ed to the scrambled CRC; identify for each mobile stationof the first group, a matched mobile station based upon the first dataof a mobile station of the first group effectively matching the seconddata of a mobile station of the second group; and generate a descrambledinformation element for each matched mobile station of the first groupby using the first scrambling sequence that is associated with thematched mobile station to descramble the scrambled information elementof the mobile terminal of the second group that is matched to the mobileterminal of the first group.
 8. The mobile station according to claim 7,wherein the threshold distance of the first mobile station relates to adistance at which the mobile station is able to receive the signals ofthe plurality of mobile stations.
 9. The mobile station according toclaim 7, wherein the threshold requirement is at least a defined signalstrength, a defined signal quality or a successful decoding of an uplinkpacket.
 10. The mobile station according to claim 7, wherein the networkentity comprises a relay station or a base station.
 11. The mobilestation according to claim 7, wherein the second group of mobilestations comprises a single mobile station.
 12. The mobile stationaccording to claim 7, wherein the second group of mobile stationscomprises a plurality of mobile stations.